Nanasaheb Peshwa (also called Balaji Bajirao )(born ???? - Died 1761) was one of the Peshwa rulers of Pune, India and the most influential person in the development of the city. During his 20 year reign (1740 to 1761), he completely transformed the village into a city. He established many new neighbourhoods (called peths) like Sadashiv Peth, Nana Peth, Shukrawar Peth, etc. He built the famous Parvati temple atop a hill that overlooks the city and built the first permanent bridge across the river Mutha. (That bridge was made of wood, so the new concrete bridge that stands at the same location today is also called LakDi Pool or 'the wooden bridge'). He also established a reservoir at the nearby town of Katraj to provide clean running water to the city. The 250 year old system is still functioning, but parts of it have been destroyed by careless development.

Maratha power in India reached its peak under his reign. Nanasaheb lost his son and brother at the Battle of Panipat. He could not recover from the shock, and died soon after the debacle. He as suceeded by his second son Madhavrao Peshwa.